Oh, come on now. I've asked you repeatedly how one is supposed to address one's buoyancy at deeper dives (say 30 meters or so). Have I received one response? It is a question that others have asked, but you've avoided it.
If you demand that people answer your questions, shouldn't you demand of yourself to answer questions asked of you?
This has been covered already (at least in piecemeal), but here it is again (in summary form):
If the dive is in warm water with no wetsuit, the depth is basically irrelevant to buoyancy. When the diver adds a wetsuit and as the wetsuit gets thicker, depth starts to become an increasing issue. A 3 mm shorty should not cause anyone an unmanageable problem on a 40m dive, and I regularly dive a full 3mm farmer-john. Keep in mind that I've got a lot of practice, low body fat and big lungs. An obese person would have a different limitation. A 3mm jumpsuit is easier than a 3mm farmer-john, and a 2/3mm even easier, etc.... These scenarios encompass a large fraction of recreational diving. So there are , I think, real and significant benefits to divers having these skills.
With wetsuits thicker than 3mm, I would think that most all divers would want to, and should, use a BCD unless the dive is going to be restricted to only very shallow depths where the buoyancy shift is reduced. For any normal human, a dive to 40m in a 7mm wetsuit will need the specialty equipment of a BCD to be done with buoyancy control throughout the dive profile.
I have never said that no one should use a BC for scuba diving. Only that divers should have the knowledge and ability to conduct an appropriately structured dive (planning for suit thickness, tank size and depth profile) without relying on a BC for buoyancy control. Have the skills and know your limits/abilities. I think that if this was a baseline for diver training, there would be some long term benefits that would result in better weight management skills among the diving populations. Others disagree with this premise.
With the core skills of weight management mastered, by all means get the BC specialty, the drysuit specialty, etc.... In cold climates the BC specialty may need to be bundled with the basic certification. Maybe the no BC diving would be restricted to some subset of the pool sessions only. Maybe one OW dive that is depth restricted could be included in a thicker wetsuit just to show that they can plan and execute the dive. That's probably not as robust a situation as someone getting trained in tropical waters, but it could still have some long term benefits to weighting skills.
Anyway, the bulk of diving instructors do not appear to be onboard with this idea. It would require new training for most instructors before it could be taught, so their resistance is understandable. Bottom line, it's not going to be pushed up to the agencies from the bottom. The other alternative is to do it top down and start a new training organization to do it. That seems extremely unlikely as well. So at this point, all this discussion is nothing more than a gedanken experiment, but maybe it will motivate someone out there to think more about improving their weight management skills. If so, this will have been a useful discussion.
I hope this answers your question. I'd still appreciate an answer to my question. In a PM would be prefered, as it is not relevant to the thread topic.